Rail flaw detector mechanism



A N V 19350 c B RQEDE 2,@3@,$29

RAIL FLAW DETECTOR MECHANISM Filed April 27, 1932 2 Sheets-Sheet l INVENTOR Bv Chafls B. Home ATTORNEY pril 7 193.

c. B. ROEDE 32,03,829

RAIL FLAW DETECTOR MECHANISM Filed April 27, 1932 2 Sheets-Sheet 2 TO AMPLIFIER T0 AMPLIFIER r0 AMPLIFIER TOAMPLIFIER Ta AMPLI IER INVENTOR Cnau-les BJRoede ATTORNEY ill ntcnted Apr. 7, 1936 ration of New York Application April av, use, Serial No. tram (pins-ran i l invention relates to rail flaw detector an paratus oi the type employed on the well-known Sperry rail flaw detector carsn In these cars the detector equipment comprises a source of current within the car, which is supplied to the rail by cans of brushes to send the current through the rail and establish an electromagnetic field surrounding the same. Any variations in this iield caused by the presence of internal fissures are picked up during the movement oi the car by means of induction coils which are maintained a constant distance above the rail surface so that normally they cut a constant number oi lines oi iorce, but on encountering the region oi a flaw they will cut a diiterent number oi lines oi iorce. Iihe coils are connected in opposition so that variations in current supply will not have any edect on the output oi said coils, while the presence of a flaw will cause one coil to out more lines oi l'orce than the other and hence generate a diderential E. M. F.

it has been found desirable to employ more than two coils for the reasons set forth in the patent to Harcourt C. Drake, l lo. 1,960,968, granted May 29th, 1934 for Flaw detector unit. The chief advantage oi such an arrangement is that it avoids the condition which arises when one coil is symmetrically located with respect to the railhead. in such position a coil is apt to miss a centrally located fissure because such a fissure causes increase and nation of flux at the sides, and the coil adds up the increase and dution to yield the same total flux as in a sound part of the rail. in said patent there is disclosed the use of two pairs oi. coils in staggered relation whereby the deiect just described is avoided because each coil coacts with only one side oi the railhead and thereiore does not sum up the total of increase and diminu tion oi flux. I have found that it is possible to till) obtain the same result now obtained by the use oi two pairs oi coils by utilizing only three coils suitably connected and positioned.

it is a further object oi my invention to provide a detector unit which will consist out a plurality oi sets oi detector coils, each set comprising three cells.

it is a further object oi my invention to provide a detector unit comprising an odd number oi coils more than one in nber, that is, three, iive, or any greater nber.

his a iurther object oi my invention to pro vide a detector unit which will comprise several sets oi detector coils, each set consisting oi an odd number oi coils greater than one.

in the coils as heretoiore employed, there was utilized a core substantially U-shaped, the arms oi said U extending downwardly into close proaimity oi the rail. 1 have iound that it is desirable tt the inner arm oi said U be shortened DETEETOE hit/ll Charles B. Reade, .lerscy wity, N. .l., Sperry Products, Inc., Broo i N. a corpu or entirely w indications were caused.

Still further objects and advantages oi this invention will become apparent in the following detailed description thereof.

In the accompanying drawings,

Fig. l is a side elevation of a portion oi a Sperry rail flaw detector car showing the detector mechanism suspended therefrom.

Figs. 2-7, inclusive, are plan views, largely diagratic, showing the various coil arrangements oi the detector unit.

Fig. 8 is a vertical section through a detector unit shog improved core for theinduction coil.

Fi 9 big. it.

Figs. ill-id, inclusive, are wiring diagrams showing various methods oi electrically connecting the coils disclosed in Figs. 2-7, inclusive.

Referring to Fig. i, there is disclosed a detector mecsm such as is employed on the Sperry detector car. a portion oi the car body it is shown having suspended therefrom the current brush carriage i i whose trout and rear sets oi brushes it and it are designed to lead current into and out oi the rail R, the said current being supplied irom a source of current (not shown) within the car. The current brush carriage supports in turn the searching unit or detector carriage it by means such as bolts and springs it, Ill. Said carriage may ride along the rail on any suitable means, such as rollers it, and supports is an end elevation oi the core shown in thereon, by any suitable means, such as bolts it posed so that only the did'erential E. M. It. genl erated by said pair oil coils resulted when a flaw was encountered. Said E. M. i k, aiter being suit-=- ably amplified, was caused to operate any suitable indicating means such as a recorder.

in the patent to Harcourt U. Drake, No. 1,960,968, there is disclosed the idea oi employing a plurality oi pairs oi detector coils, the coils oi each pair being opposed. Thus, iour, or any even number oi coils, could be employed either in staggered relation as shown in said application or, in line. in this invention i have disclosed a method by which it can obtaim by the use oi three cells the as results as are obtained by said. patent by the use oi. two pairs oi coils. For this pse I may employ the artill lid

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, as to unbalance said unit and rangement shown, for example, in Figs. 1 and 2. In Fig. 1 the coils are shown enclosed in cylinders 25 mounted within the search unit 2|. Said coils may be arranged as shown in Fig. 2. Here it will be seen that one coil 30 is displaced with respect to two other coils, 3| and 32. By suitably interconnecting said three coils I have disclosed how the same effect is obtained as in the case of two pairs of coils in staggered relation. Thus, referring to Fig. 14, it will be seen that coils 30 and 3| act as one pair of coils and 30 and 32 act as another pair. The unit as a whole is balanced so that for a variation which affects all three coils, such as a variation in the current supply, there will be no output, that is, no differential E. M. F., because the output of coils 3| and 32 is equal and opposed to that of coil 30. This may be accomplished either by providing half the number of windings on each coil 3| and 32 as are employed on coil 30 or else by varying the air gap between the coils. and the rail surface, or by any combination of variations in air gap or in windings so that the sum total of the output of said coils when all are caused to respond simultaneously to the same changing electromagnetic field will be zero. On entering the region of a flaw, it will be seen that coil 3|, for example, will first cut a different number of lines of force so then each of the remaining coils 30 and 32 on passing through a region of flaw. will also unbalance the unit, so that three separate indications, each comprising a positive and negative impulse, will be obtained. The coils are so positioned that these impulses are additive, especially since said impulses may first be rectified as disclosed in the patent to Harcourt C. Drake, No. 1,955,953, granted April 24, 1934.

In Figs. 1043, inclusive, I have shown still other methods of interconnecting the set of three coils so that the equivalent of two pairs of opposed coils is obtained. In these forms, all of the coils are the same, that is, they have the'same number of turns. In Fig. 10, for instance, coil 3| is equal to and opposed to coil 30. Said two coils act as a pair. Similarly, and opposed and act as I have in effect provided have utilized one common a pair. In other words, two pairs of coils but I coil in each pair. In

Fig. 11, a slightly modified arrangement givesthe output between coils 30 and 3| equal and opposite to the output between coils 30 and 32. Thus, while the pair of coils 30 and 3| may give an impulse first positive and then negative, the output between coils 30 and 32 would give an impulse first negative and @1811 positive.

In Fig. 12 I have shown stilfanother form of wiring wherein coils 3| and 30 form one pair, while 3| and 32 form'the other pair. In Fig. 13, the form of wiring shown in Fig. 12 has been modified to give the opposite phases in the same manner as in Fig. 11. The three coils may be arranged as shown in Fig. 2 with one coil staggered laterally across the rail with respect to the other two coils, or they may be arranged in line as shown in Fig-3.

A somewhat different arrangement is disclosed in Fig. 4 wherein the end coil is offset laterally with respect to the other two coils instead of the middle coil being ofl'set as disclosed in Fig. 2.

In Fig. 5 is shown still another arrangement of the set of coils wherein said coils are progressively offset laterally so that each coil coacts with a different portion of the rail surface as the car moves along the rail.

' to surface burns.

coils 30 and 32 are equal- If desired, two sets of coils, each set comprising three coils, may be employed and said coils may be arranged in any of the arrangements disclosed in Figs. 2-5 inclusive. Thus, in Fig. 6 I have shown two sets of coils, each set arranged as shown in Fig. 2.

It will be understood that the coils of each set are so positioned that when suitably rectified the impulses from the various coils are additive. Also, when several sets of coils are employed as in Fig. 6, not only are the impulses of the coils within each set additive, but the sets are so positioned that the impulses from one set are added to the impulses from the other set. In this manner a protracted impulse is obtained which is capable of actuating indicating mechanism without danger of a flaw being missed.

While I have described an arrangement of three coils above, the same principle may applyto any odd number of coils, as, for example, five coils, as shown in Fig. '7, which would ordinarily do the work which heretofore required at least four pairs of opposed coils. A material reduction in the number of coils and in the space required for such a unit is therefore obtained. Thus, coils 40 and 4| is one pair, 4| and 42 a. second pair, 42 and 43 a third pair, and 43 and 44 a fourth pair.

In Fig. 6 form I do not limit myself to two sets of coils where each set comprises but three, coils, since each set may consist of any odd number of coils, three or more.

In Fig. 8, where the coils are shown offset so that the, inner end of the core 50 would coact with a portion of the railhead nearer the center thereof than the outer end, it was found desir able to out off the inner arm and thereby eliminate indications due to surface irregularities and The core, therefore, appears as. shown in Figs. 8 and 9 with only the outer end thereof provided with a downwardly extending arm 5|.

In accordance with the provisions oi. the patent statutes, I have herein described the principle and operation of my invention, together with the apparatus which I now consider to represent the best embodiment thereof, but I desire to have it understood that the apparatus shown is only illustrative and that the invention can be carried out by other means. Also. while it is de signed to use the various features and elements in the combination and relations described, some of these may be altered and others omitted without interfering with the more general results outlined, and the invention extends to such use.

Having described my invention, what I claim and desire to secure by Letters Patent is:

1. In a device for detecting flaws in rails, a detector unit, said unit comprising an induction coil having a core extending therethrough, only having an arm extending downwardly adjacent the rail surface.

2. In a device for detecting flaws in rails, a detector unit, said unit comprising an induction coil having a. core extending therethrough, one end of said coil and said core being positioned nearer the center of the rail than the other end, only the latter end of said core being providedwith an arm extending downwardly adjacent the rail surface.

3. In a device for detecting flaws in electrical conductors, said device having means for passing current through the conductor to establish an electromagnetic field, a detector unit, said unit? comprising three coils oonductively connected aosasco and in inductive relation to said conductor, each of said coils comprising a plurality of substantially parallel turns, each coil being positioned with its axis substantially at right angles to the direction of current flow through the conductor.

4. In a device for detecting flaws in electrical conductors, said device having means for passing current through the conductor to establish an electromagnetic field, a detector unit, said unit comprising three coils conductively connected in balanced relation and in inductive relation to said conductor, each of said coils comprising a plurality of substantially parallel turns, each coil being positioned with its axis substantially at right angles to the direction of current flow through the conductor.

5. In a device for detecting flaws in electrical conductors, said device having means for passing current through the conductor to establish an electromagnetic field, a detector unit, said unit comprising an odd number of coils more than one, conductively connected and in inductive relation to said conductor, each of said coils comprising a plurality of substantially parallel turns, each coil being positioned with its axis substantially at right angles to the direction of current flow through the conductor.

6. In a device for detecting flaws in electrical conductors, said device having means for passing current through the conductor to establish an electromagnetic field, a detector unit, said unit comprising an odd number of coils more than one, conductively connected in balanced relation and in inductive relation to said conductor, each of said coils comprising a plurality of substantially parallel turns, each coil being positioned with its axis substantially at right angles to the direction of current flow through the conductor.

'2. In a device for detecting flaws in electrical conductors, said device having means for passing current through the conductor to establish an electromagnetic field, a detector unit, said unit comprising three coils conductively connected and in inductive relation to said conductor, each of said coils comprising a plurality of substantially parallel turns, each coil being positioned with its axis substantially at right angles to the direction of current fiow through the conductor, one of said coils being balanced against the other two coils.

8. In a device for detecting flaws in electrical conductors, said device having means for passing current through the conductor to establish an electromagnetic field, a detector unit, said unit comprising three coils conductively connected and in inductive relation to said conductor, each of said coils comprising a plurality of substantially parallel turns, each coil being positioned with its axis substantially at right angles to the direction of current flow through the conductor, one of said coils coacting witheach of the other coils.

9. In a device for detecting flaws in electrical conductors, said device having means for passing current through the conductor to establish an electromagnetic field, a detector unit, said unit comprising an odd number of coils conductively connected and in inductive relation to said conductor, each of said coils comprising a plurality of substantially parallel turns, each coil being positioned with its axis substantially at right angles to the direction of current flow through the conductor, certain of said coils each coacting with a plurality of the other coils.

10. In a device for detecting flaws in electrical conductors, said device having means for passing current through the conductor to establish an electromagnetic field, a detector unit, said unit comprising a plurality of sets of coils, each set comprising three coils conductively connected and in inductive relation to said conductor, each of said coils comprising a plurality of substantially parallel turns, each coil being positioned with its axis substantially at right angles to the direction of current flow through the conductor.

11. In a device for detecting flaws in electrical conductors, said device having means for passing current through the conductor to establish an electromagnetic field, a detector unit, said unit comprising a plurality of sets of coils, each set comprising three coils conductively connected in balanced relation and in inductive relation to said conductor, each of said coils comprising a plurality of substantially parallel turns, each coil being positioned with its axis substantially at right angles to the direction of current flow through the conductor.

12. In a device for detecting flaws in electrical conductors, said device having means for passing current through the conductor to establish an electromagnetic field, a detector unit, said unit comprising a plurality of sets of coils, each set comprising an odd number of coils conductively connected and in inductive relation to said conductor, each of said coils comprising a plurality of substantially parallel turns, each coil being positioned with its axis substantially at right angles to the direction of current flow through the conductor.

13. In a device for detecting fiaws in electrical conductors, said device having means for passing current through the conductor to establish an electromagnetic field, a detector unit, said unit comprising a plurality of sets of coils, each set comprising an odd number of coils conductively connected in balanced relation and in inductive relation to said conductor, each of said coils comprising a plurality of substantially parallel turns, each coil being positioned with its axis substantially at right angles to the direction of current flow through the conductor.

14. In a device for detecting flaws in rails, said device having means for passing current through the rail to establish an electromagnetic field, a

detector unit, said unit comprising three coils conductively connected and in inductive relation to the rail, each of said coils comprising a plurality of substantially parallel turns, each coil being positioned with its axis substantially at right angles to the direction of current flow through the conductor, one of said coils being displaced with respect to the remaining coils laterally of the rail.

15. In a device for detecting flaws in rails, said device having means for passing current through the rail to establish an electromagnetic field, a detector unit, said unit comprising an odd number of coils conductively connected and in inductive relation to the rail, each of said coils comprising a plurality of substantially parallel turns,

each coil being positioned with its axis substantially at right angles tothe direction of current fiow through the conductor, certain of said coils being displaced with respect to the remaining coils laterally of the rail.

CHARLES B. ROEDE. 

